Abstract The fractional step method is an efficient time advancement scheme for problems involving transient incompressible flow. The method is desirable over traditional SIMPLE-like algorithms for its non-iterative nature. This paper presents a technique that extends the fractional step method to low-Mach number compressible flow problems. The proposed pressure-velocity coupling and a transient SIMPLEC algorithm are validated and verified for a 1D acoustic wave propagation and a convective isentropic vortex to qualitatively evaluate their convergence properties. Next, both algorithms are used to predict aerodynamic and aeroacoustic behaviour of flow past a wall-mounted side mirror. The proposed scheme is stable at acoustic CFL number greater than one, and at convective Co number equal one. The L2 error norms of both schemes exhibit second order accuracy as grids are refined, while the new scheme requires significantly less computation effort for an equal error. The new fractional step method consumes only 20% to 35% of the computation effort that is required by the transient SIMPLEC algorithm for the same error, and is easily scalable to a greater number of CPU processors.

中文翻译：

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用于低马赫数空气动力学和空气声学的快速瞬态求解器

摘要 分数阶跃法是解决瞬态不可压缩流问题的一种有效的时间推进方法。由于其非迭代性质，该方法优于传统的类似 SIMPLE 的算法。本文提出了一种将分数阶跃法扩展到低马赫数可压缩流动问题的技术。所提出的压力-速度耦合和瞬态 SIMPLEC 算法针对一维声波传播和对流等熵涡旋进行了验证和验证，以定性评估它们的收敛特性。接下来，这两种算法都用于预测流过壁挂式侧镜的空气动力学和空气声学行为。所提出的方案在声学 CFL 数大于 1 和对流 Co 数等于 1 时是稳定的。随着网格的细化，两种方案的 L2 误差范数都表现出二阶精度，而新方案对于相同的误差所需的计算工作量要少得多。对于相同的错误，新的分数步法仅消耗瞬态 SIMPLEC 算法所需计算工作量的 20% 到 35%，并且可以轻松扩展到更多 CPU 处理器。